Pharmaceutical Sciences Research Opportunities

Christine Dengler-Crish, Ph.D.

Colocalization of αVβ Integrins with Neurons and Glia in Hippocampus of Alzheimer’s Model Mice

A major goal of our laboratory is to understand some of the earliest pathological mechanisms that contribute to Alzheimer’s brain pathology. Decades prior to the first signs of cognitive deficits, tau pathology begins to accumulate in the brain, yet in fully symptomatic disease stages, spread of brain tauopathy closely correlates with progression of cognitive decline. There is a critical need to understand the factors fueling progression of tauopathy across these disease stages, and this defines the overall purpose of our research to identify early disease mechanisms that can be targeted to prevent onset of dementia.

A potential contributor to tauopathy progression involves the dysfunctional signaling of cell surface integrins. In the healthy adult brain, integrins are expressed ubiquitously and play important roles in neural plasticity. Recent studies have suggested that changes in expression levels and function of specific integrin subtypes may be associated with onset and spread of Alzheimer’s brain pathology. Our lab has preliminary data showing that αVβ1 and αVβ5 integrins are dramatically upregulated in hippocampus of transgenic tauopathy model (htau) mice, and this increase occurred over a 5 month period as these animals aged from presymptomatic (5mo.) to symptomatic ages (10 mo.). The proposed project will work to determine whether αVβ1 and αVβ5 integrins in the hippocampus colocalize with neurons, astrocytes, or microglia in presymptomatic and symptomatic aged htau Alzheimer’s disease model mice. Student fellows will be expected to work with brain tissue obtained from mice to conduct immunofluorescence assays to label αVβ integrins in target brain regions and use microscopy imaging techniques to identify cell types and quantify integrin distributions.

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Sheila Fleming, Ph.D. – 1

Gene-Environment Interactions in Parkinson’s Disease

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder and is characterized by the loss of dopaminergic neurons in the substantia nigra and the development of lewy bodies and lewy neurites in the brain and periphery. While the cause of the majority of cases is unknown, it is generally considered that gene-environment interactions underlie most cases of PD. Therefore, the identification of gene-environment interactions associated with PD-like pathology and neurodegeneration is an important goal in the field. ATP13A2 is a P5-ATPase of the P-type ion transport ATPase superfamily and loss of function mutations cause the neurodegenerative condition Kufor-Rakeb Syndrome, an autosomal recessive form of PD. The function of ATP12A2 is unclear but in vitro studies suggest it may be involved in the lysosomal degradation of proteins, polyamine and heavy metal transport (manganese and/or zinc), and mitochondrial function, all mechanisms that can overlap with PD. An important next step is to determine how loss of function of ATP13A2 in vivo interacts with environmental factors such as heavy metals and toxicants that interfere with cellular transport, protein degradation, and mitochondrial function. It is hypothesized the loss of ATP13A2 function causes an increased vulnerability to the toxic effects of certain heavy metals and pesticides associated with PD. This hypothesis will be tested using Atp13a2-deficient mice that have been shown to develop age-dependent motor impairments, enhanced accumulation of lysosomal storage material, and increased accumulation of the PD protein alpha-synuclein. Wildtype and Atp13a2-deficient mice will be exposed to different metals and toxicants associated with PD (ex. manganese). Sensorimotor function will be measured and in the brain accumulation of the PD protein alpha-synuclein and neurodegeneration will be determined. A combination of behavioral, cellular, and molecular techniques will be employed.

Sheila Fleming, Ph.D. – 2

The Effect of Exercise in Parkinson’s Disease

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder and is characterized by the loss of dopaminergic neurons in the substantia nigra and the development of alpha-synuclein positive lewy bodies and lewy neurites in the brain and periphery. The cardinal motor symptoms in PD (rigidity, resting tremor, bradykinesia, postural instability) are well studied and can be managed to a certain extent with dopamine replacing therapies. However, there are also a host of non-motor symptoms that can negatively impact the quality of life for people with PD. Cognitive dysfunction is one of those symptoms. It is common and can progress to dementia over time. Unfortunately, how dementia develops in PD is unclear. In this project we are working to develop a new model of PD that develops dementia. In addition, we will examine whether exercise therapy using treadmill running can protect against the development of cognitive dysfunction and dementia in our new rat model.

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Takhar Kasumov, Ph.D.

Role of Alcohol-Induced Acetylation in Alzheimer’s Disease (AD)

Alcohol (EtOH) consumption, prevalent in the United States, is strongly associated with an elevated risk of late-onset Alzheimer’s disease (AD), a leading cause of dementia. Excessive alcohol intake increases the likelihood of AD by a staggering 300%, underscoring the urgent need to investigate the link between Alcohol Use Disorder (AUD) and increased AD risk. A possible AUD-AD connection may stem from disrupted brain protein homeostasis due to EtOH metabolism. Post-translational acetylation at lysine side chain of proteins by acetyl-CoA (AcCoA) has emerged as an essential regulatory mechanism in protein stability, intermediary metabolism, and epigenetics. EtOH detoxification produces AcCoA and depletes NAD+, key factors involved in acetylation. Tau acetylation is implicated in tauopathy, accumulation of hyperphosphorylated microtubule-associated protein tau (p-tau), in AD. Yet, how alcohol metabolism is linked to altered acetylation of tau in AD remains unknown.
Site-specific tau acetylation dynamic in tauopathy is poorly understood, and the influence of alcohol on acetylation-dependent tauopathy remains entirely uncharted. EtOH metabolism-induced NAD+ deficiency may hinder brain deacetylation, potentially disrupting tau turnover and increasing p-tau accumulation. As EtOH-derived acetate contributes to mouse brain histone acetylation, it may also induce epigenetic alterations linked to tauopathy. Hence, the EtOH-induced shift in site-specific acetylation dynamics, rather than mere changes in acetylation levels, can influence brain function through epigenetic mechanisms and p-tau aggregation.

Our group developed a mass spectrometry (MS)-based method to examine acetylome dynamics in vivo. Here, we aim to employ this method to establish a connection between AUD and AD. The central hypothesis is that alcohol-induced altered brain acetylation dynamics contribute to the accumulation of toxic acetylated tau.

We will measure site-specific acetylation turnover of histones and tau in the hippocampus and cortex of alcoholic htau mouse model of tauopathy to determine whether the altered acetylation results from impaired acetylation or deacetylation. Utilizing ChiP-Seq, we will identify histone acetylation-regulated transcriptional changes to uncover modified signaling pathways.

The impact. This study will also establish the feasibility of the acetylome dynamics method, which also can be used to investigate the selectivity and specificity of deacetylase and acetyltransferase inhibitors or activators in vivo and motivate the development of new AD therapies.

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Xinwen Wang, Ph.D.

Remimazolam Pharmacogenetics

Annually in the United States, over 100,000 deaths and 2 million hospitalizations occur due to drug adverse reactions. With nearly 40 million anesthetic and sedative administrations yearly, and over 2 million reported complications, optimizing these medications is crucial for patient safety, comfort, and procedural success.
Remimazolam (Byfavo®), a recently approved ester-linked benzodiazepine for sedation by the US FDA, offers distinct advantages in sedation with its rapid action and predictable duration, highly suitable for widespread anesthesia use. However, its notable interindividual variability in patient responses, accompanied by an adverse effect rate surpassing 50%, poses a significant challenge, leading to patient distress and procedure failure. Consequently, there is an urgent clinical need for optimizing remimazolam use to improve the sedative/anesthetic outcomes.

The favorably short and predictable action of remimazolam is largely attributed to its fast metabolism, primarily involving the hydrolysis of its ester group. Thus, the hydrolysis of remimazolam plays a crucial role in its deactivation, which in turn significantly influences its action duration, overall efficacy, toxicity, and contributes to the variability in its response. Nevertheless, the enzyme(s) responsible for the hydrolysis of remimazolam remain controversial. Carboxylesterase1 (CES1) serves as the primary hepatic hydrolase in humans, participating in the metabolism of numerous therapeutic agents. Significant interindividual variability in expression and activity of CES1 has been consistently reported. Our previous publications have demonstrated that the CES1 genetic polymorphisms and inhibitors are associated with significantly altered metabolism and/or efficacy of several selective CES1 substrate drugs. Given the ester structure of remimazolam, characterized by a small alcohol group and large acyl group, which aligns with the substrate preference of CES1, however, the experimental evidence identifying the enzymes responsible for remimazolam hydrolysis remains lacking. The overarching objective of this proposal is to identify the enzyme responsible for remimazolam deactivation and to determine the impact of genetic polymorphisms on remimazolam deactivation. Our central hypothesis is that the remimazolam is deactivated by CES1 and functional CES1 genetic polymorphisms can significantly affect the remimazolam deactivation in human liver. The central hypothesis will be examined in two specific aims:

Aim1: To identify the enzyme responsible for CES1 deactivation. Human liver and intestine s9 fractions, human plasma, CES1 and CES2 recombinant enzymes will be used to test the hypothesis that remimazolam is deactivated by hepatic CES1 specifically.

Aim2: To examine the impact of CES1 genetic polymorphism on the deactivation of remimazolam in vitro.

We will assess the impact of CES1 G143E on remimazolam deactivation using wild type CES1, CES1 G143E, and vector transfected cell lines.

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